Growth and nutrition of normal full-term infants from birth to 8 months of age is being studied by a variety of approaches. Daily intakes of food are determined and measurements of length, weight, skinfold thickness and serum biochemical parameters are made at regular intervals. Specially prepared, ready-to-feed formulas are employed. Representative studies concern: (1) Factors that influence food intake by infants (e.g., caloric density of the food, precentage of calories supplied from fat, sweetness of the food); (2) Requirements for protein and essential amino acids; (3) The influence of consuming whole milk on gastrointestinal blood loss; (4) Requirements for zinc. Metabolic balance studies are being employed to determine the influence of dietary intake of protein on urinary excretion of various minerals, especially calcium.